Covering for bodies impelled through water.



No. 632,738. Patented Sept. I2, I899.

J. UHARA.

COVERING FOR BODIES IMPELLED THROUGH WATER.

(Application filed Dec. 2, 1898.)-

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* NITED STATES PATENT QFFICE.

JAMES OHARA, OF TORONTO, CANADA.

COVERING FOR, BODIES IMPELLED THROUGH WATER.

SPECIFICATION forming part of Letters Patent No. 632,738, datedSeptember 12, 1899.

Application filed December 2, 1898. Serial No. 698,057. (No model.)

To all whom, it may concern: I

Be it known that 1, JAMES OHARA, a subject of the Queen of GreatBritain, residing at Toronto, in the county of York, Province ofOntario, Dominion of Canada, have invented a new and useful Covering forBodies Impelled Through \Vater, of which I do hereby declare that thefollowing is a full, clear, and exact specification, such as will enableothers skilled in the' art to which the invention appertains to make anduse the same- Myinvention relates to coverings for bodies impelledthrough water, and has for its object to lessen the attraction betweenthe body and the water and the cohesion of the latter, whereby thebodyimpelled is more efiectively cleared of what is known as deadwater,thus materially reducingthe resistance caused by such water andutilizing to a fuller extent the impelling force wasted in overcomingthat resistance.

Ships skins,the surfaces of propeller-blades, and similar marine bodiesas now constructed are made as smooth and even as possible with a viewto offering the least possible resistance. With this construction it isfound that the vessels or other bodies cannot clear themselves of Whatis generally called dead water, but will during their progress carrywith them at the expense of the propelling power a large amount of thesurrounding water. The dead water is not only dragged along by thevessel or similar structure, but is also pushed in front thereof in alarge body, which will fail to divide until heaped forward of the bowsof the vessel or like projections of similar structures. This pushingand dragging of the water is caused by its cohesion. The result of thisis that a large part of the propelling power must be expended inovercoming the resistance of this pushing and dragging water. To obviatethis difficulty as much as possible, vessels are tapered not only at thebow, but from midships to stern, making the lines forward and aft asfine as possible, whereby the vessel is enabled to divide the water morecleanly at the bows and to clear itself of the surrounding water whichis being dragged after it; but even with this construction, however finethe lines may be, the difficulty is far from being removed.

The same difliculty attends the driving of the blades of thepropellerscrew through the water. In order to propel the vessel, theblades must continually pass through the water, taking in new water andforcing it to the rear. If the screw is driven too fast, it will carryaround with it the whole body of water in which it is moving, which willprevent its taking in new water or making much forward movement. Thiscondition is due to the same cause of cohesion. If the blades couldcontinually pass through the water and not drag it with them, the fasterthe screw revolved the greater would be the propelling force obtained.My invention is intended to meet or remove or modify these difficultiesand enable a ship to clear herself of dead water and also to enable thescrew-blades better to pass through the water and free themselves of it.

I have discovered that the cohesion of the water may be counteracted andneutralized by producing vibration in a very thin stratum of water nextto the object so passing through the water. It is obvious that with aperfectly smooth and even surface below the water-line there will be novibration, and therefore the cohesion of the water is allowed to actwith greater force, and hence the more difficult it is to propel thevessel. It does not follow, however, that roughness or unevennesswithout design will facilitate the movement of any solid body whenpassing through water. To accomplish this result, I make the surface ofthe moving body imbricated or shingle-like, the parts corresponding toshingles being of the form and arranged on and attached to the body, ashereinafter described.

Then the imbricated surface is applied to a ships hull, the water-shedis from how to stern. lVhen applied to propeller-blades, it is in theopposite direction to the forward movement of the blades.

My invention is illustrated in theaccompanying drawings, which show theapplication of the invention to the hull of a ship, and in which Figurel is a side view in elevation of the ships hull; Fig. 2, a detail planof one of the imbricated segments, and Fig. 3 a detail perspective ofsame.

Referring to the drawings, A is one of the duce a Vibrating stratum ofwater around the vessel. It is not necessary that each imbricatedsegment should be a whole plate. There may be many imbricated segmentson one plate integral therewith. The rear edges a of each segment arebeveled or reduced in rolling or molding. The segments are arranged inrows B, so that they break joint, the rounded end of one segment beingopposite the junction of two adjoining segments of the succeeding row.In the case of a vessel the length of a segment should be from one inchto two feet and the width of about the same dimensions, according to thesize or tonnage of the vessel, and the imbrication should show at theafter end a drop or fall of from one quarter of an inch to two inches,according to the length of the segment. The dimensions for thepropeller-blades should vary in accordance with the above.

It is obvious that any suitable arrangement of the overlapping portionsor segments formin g an imbricated surface adapted to produce avibrating stratum adjacent to the moving body may be applied to thesurface of the body without departing from the principle of myinvention.

From the foregoing description it will be seen that my invention willcreate a vibration of the water surrounding the vessel or other bodythat will tend to break up the co hesion of the water and will enablethe body to pass through the Water without carrying the usual burden ofdead water.

Having thus described myinvention, what I claim is- 1. A covering forbodies impelled through water consisting of an imbricated surface,the

imbricated portions thereof arranged with V the overlapped or thin edgestoward the direction of the forward movement of the impelled body,substantially as described.

2. A covering for bodies impelled through water consisting of imbricatedsegments having their thin ends pointing in the direction of forwardmovement of body, and arranged in rows in which the segments of each rowbreak joint with the segments of the succeeding row, substantially asdescribed.

In testimony whereof I hereunto aflix' my signature in the presence oftwo witnesses.

JAMES OHARA.

